Pub Date : 2024-07-27DOI: 10.1134/s1052618824700237
I. V. Pashkov
Abstract
The Gough–Stewart platform has occupied an important place in the manufacturing and scientific industries, making it possible to facilitate various production cycles or conduct necessary research. Its development makes it possible to solve newer and more complex problems or facilitate the implementation of existing ones. This article considers a modification of the classical platform; considers solutions to direct and inverse kinematics problems; implements a visualization program and a control algorithm, both a physical model of the platform and a virtual one; and estimates the parameters of the platform. Direct and inverse kinematics problems are one of the main problems that describe the platform; on their basis, it is possible to consider the behavior of the platform in various configurations of the given parameters. The visualization program allows one not only to view the behavior of the platform without the need to use a physical model of the platform, but also to control the real platform by transmitting the appropriate signals to the control circuit.
{"title":"Modification of the Gough–Stewart Platform with Six Degrees of Freedom","authors":"I. V. Pashkov","doi":"10.1134/s1052618824700237","DOIUrl":"https://doi.org/10.1134/s1052618824700237","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The Gough–Stewart platform has occupied an important place in the manufacturing and scientific industries, making it possible to facilitate various production cycles or conduct necessary research. Its development makes it possible to solve newer and more complex problems or facilitate the implementation of existing ones. This article considers a modification of the classical platform; considers solutions to direct and inverse kinematics problems; implements a visualization program and a control algorithm, both a physical model of the platform and a virtual one; and estimates the parameters of the platform. Direct and inverse kinematics problems are one of the main problems that describe the platform; on their basis, it is possible to consider the behavior of the platform in various configurations of the given parameters. The visualization program allows one not only to view the behavior of the platform without the need to use a physical model of the platform, but also to control the real platform by transmitting the appropriate signals to the control circuit.</p>","PeriodicalId":642,"journal":{"name":"Journal of Machinery Manufacture and Reliability","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141776072","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-27DOI: 10.1134/s1052618824700250
P. A. Vityaz, M. L. Kheifetz, N. L. Gretsky, D. N. Khilko
Abstract
Methods have been developed for monitoring and diagnosing the degree of wear and loss of the geometric shape of surfaces. A selection of technological routes was carried out for the complex restoration of working surfaces of large-sized products using electrophysical energy sources during surfacing of powders and wires. It has been shown that the cost of major repairs when restoring a screw shaft is, on average, two times lower than manufacturing a new one. It is important to monitor regularly the degree of wear of shaft turns and their local restoration using surfacing materials and technologies.
{"title":"Reverse Engineering in Production and the Repair Complex Profile and Large-Sized Products","authors":"P. A. Vityaz, M. L. Kheifetz, N. L. Gretsky, D. N. Khilko","doi":"10.1134/s1052618824700250","DOIUrl":"https://doi.org/10.1134/s1052618824700250","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Methods have been developed for monitoring and diagnosing the degree of wear and loss of the geometric shape of surfaces. A selection of technological routes was carried out for the complex restoration of working surfaces of large-sized products using electrophysical energy sources during surfacing of powders and wires. It has been shown that the cost of major repairs when restoring a screw shaft is, on average, two times lower than manufacturing a new one. It is important to monitor regularly the degree of wear of shaft turns and their local restoration using surfacing materials and technologies.</p>","PeriodicalId":642,"journal":{"name":"Journal of Machinery Manufacture and Reliability","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141776076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-27DOI: 10.1134/s105261882470016x
A. M. Popov, V. I. Filatov
Abstract
The tasks of forecasting a possible scenario of unintentional destructive impacts (mass impacts like voltage fluctuations, industrial electromagnetic interference, natural impacts) on a distributed automated control system are discussed. Analytical relationships are proposed to assess the consequences of such destructive impacts (signal transmission systems, communication systems). One of the possible scenarios of such impacts on the system is considered, taking into account the distribution of the intensity.
{"title":"Stability of a Distributed Automated Control System Taken into Account in a Model for Predicting the Consequences of Unintentional Destructive Impacts","authors":"A. M. Popov, V. I. Filatov","doi":"10.1134/s105261882470016x","DOIUrl":"https://doi.org/10.1134/s105261882470016x","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The tasks of forecasting a possible scenario of unintentional destructive impacts (mass impacts like voltage fluctuations, industrial electromagnetic interference, natural impacts) on a distributed automated control system are discussed. Analytical relationships are proposed to assess the consequences of such destructive impacts (signal transmission systems, communication systems). One of the possible scenarios of such impacts on the system is considered, taking into account the distribution of the intensity.</p>","PeriodicalId":642,"journal":{"name":"Journal of Machinery Manufacture and Reliability","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141776071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-27DOI: 10.1134/s1052618824700183
G. Zh. Sakhvadze
Abstract
The technology of laser impact welding of a thin aluminum plate with a stainless steel plate is discussed. Finite element simulation of the laser impact welding technology was conducted using the ABAQUS package. The results showed that the quality of the weld mainly depends on two parameters: the energy of the laser pulse and the initial distance between the plates. Conditions were established under which parameters of laser impact welding can be used to weld an aluminum plate with a stainless steel plate. The distributions of plastic strains and temperatures along the weld were obtained.
{"title":"Features of Finite Element Simulation of Laser Impact Welding of Aluminum with Stainless Steel","authors":"G. Zh. Sakhvadze","doi":"10.1134/s1052618824700183","DOIUrl":"https://doi.org/10.1134/s1052618824700183","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The technology of laser impact welding of a thin aluminum plate with a stainless steel plate is discussed. Finite element simulation of the laser impact welding technology was conducted using the ABAQUS package. The results showed that the quality of the weld mainly depends on two parameters: the energy of the laser pulse and the initial distance between the plates. Conditions were established under which parameters of laser impact welding can be used to weld an aluminum plate with a stainless steel plate. The distributions of plastic strains and temperatures along the weld were obtained.</p>","PeriodicalId":642,"journal":{"name":"Journal of Machinery Manufacture and Reliability","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141785605","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-27DOI: 10.1134/s1052618824700249
V. S. Popov, A. A. Popova
Abstract
In this paper, a mathematical model of nonlinear aeroelastic oscillations of a disk that has a suspension with hardening cubic nonlinearity and interacts with a layer of viscous gas pulsating due to a specified disturbance on its contour is presented. An asymptotic analysis, which made it possible to reduce the initial model to the generalized Duffing equation, based on the solution of which the main aeroelastic response of the disk and its phase shift were found using the harmonic balance method, was carried out. The characteristics in particular cases provide a transition to an incompressible viscous fluid and a linear elastic suspension, while their numerical study made it possible to establish that the compressibility of the gas leads to an increase in the values of the resonant frequencies and an increase in the amplitudes of the disk oscillations. Calculations showed the possibility of suppressing unstable oscillations of the disk near resonant frequencies by changing the thickness of the gas layer. The obtained results can be used to study the dynamics of gas and liquid dampers and supports, as well as sensitive elastic elements of pressure sensors.
{"title":"Mathematical Modeling of the Aeroelastic Response of a Disk Having a Nonlinear Elastic Suspension and Interacting with a Layer of Viscous Gas","authors":"V. S. Popov, A. A. Popova","doi":"10.1134/s1052618824700249","DOIUrl":"https://doi.org/10.1134/s1052618824700249","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>In this paper, a mathematical model of nonlinear aeroelastic oscillations of a disk that has a suspension with hardening cubic nonlinearity and interacts with a layer of viscous gas pulsating due to a specified disturbance on its contour is presented. An asymptotic analysis, which made it possible to reduce the initial model to the generalized Duffing equation, based on the solution of which the main aeroelastic response of the disk and its phase shift were found using the harmonic balance method, was carried out. The characteristics in particular cases provide a transition to an incompressible viscous fluid and a linear elastic suspension, while their numerical study made it possible to establish that the compressibility of the gas leads to an increase in the values of the resonant frequencies and an increase in the amplitudes of the disk oscillations. Calculations showed the possibility of suppressing unstable oscillations of the disk near resonant frequencies by changing the thickness of the gas layer. The obtained results can be used to study the dynamics of gas and liquid dampers and supports, as well as sensitive elastic elements of pressure sensors.</p>","PeriodicalId":642,"journal":{"name":"Journal of Machinery Manufacture and Reliability","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141785608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-27DOI: 10.1134/s1052618824700134
K. Nagendra Prasad, Syed Ismail, M. Satish
Abstract
Surface texturing is a promising sustainable technique to get better the machining performance of cutting tools. Laser surface texturing and micro-EDM are the most commonly used fabrication techniques and the textured tools exhibit better tool performance as compared to conventional tool. However, these processes involve resolidification of material surface which makes the surface softening and reduction in the surface hardness. In the present work, cutting performance of the high-speed steel (HSS) tool is studied by fabricating hybrid (microgrooves with dimples) textures on its rake face using both laser ablation and micro-EDM methods followed by laser shock peening without ablative coating (LSPWAC) process. Hybrid textured with shock peened HSS tools are used in orthogonal dry turning of 316 L stainless steel. It has been observed that hybrid textures with shock peened HSS tool exhibits higher tool life of up to 255 and 85% than the conventional and the hybrid textured (HT) tools respectively. The results shown that surface texturing followed by shock peening is an innovative method to improve the sustainability in machining process than only surface texturing method. Moreover, analysis of chip is studied by finite element analysis.
摘要表面纹理加工是一种很有前途的可持续技术，可提高切削工具的加工性能。激光表面纹理加工和微电火花加工是最常用的制造技术，与传统刀具相比，纹理加工刀具具有更好的刀具性能。然而，这些工艺涉及材料表面的分解，导致表面软化和表面硬度降低。在本研究中，通过使用激光烧蚀和微电火花加工方法在高速钢（HSS）前刀面上制造混合纹理（微凹槽），然后使用无烧蚀涂层激光冲击强化（LSPWAC）工艺，对高速钢（HSS）刀具的切削性能进行了研究。混合纹理冲击强化高速钢刀具用于 316 L 不锈钢的正交干车削。结果表明，混合纹理与冲击强化高速钢刀具的刀具寿命分别比传统刀具和混合纹理（HT）刀具高出 255% 和 85%。结果表明，与单纯的表面纹理加工方法相比，先进行表面纹理加工再进行冲击强化是一种创新方法，可提高加工过程的可持续性。此外，还通过有限元分析研究了切屑分析。
{"title":"High Speed Steel Tool Performance through Hybrid Texturing Followed by Shock Peening towards Sustainable Machining","authors":"K. Nagendra Prasad, Syed Ismail, M. Satish","doi":"10.1134/s1052618824700134","DOIUrl":"https://doi.org/10.1134/s1052618824700134","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Surface texturing is a promising sustainable technique to get better the machining performance of cutting tools. Laser surface texturing and micro-EDM are the most commonly used fabrication techniques and the textured tools exhibit better tool performance as compared to conventional tool. However, these processes involve resolidification of material surface which makes the surface softening and reduction in the surface hardness. In the present work, cutting performance of the high-speed steel (HSS) tool is studied by fabricating hybrid (microgrooves with dimples) textures on its rake face using both laser ablation and micro-EDM methods followed by laser shock peening without ablative coating (LSPWAC) process. Hybrid textured with shock peened HSS tools are used in orthogonal dry turning of 316 L stainless steel. It has been observed that hybrid textures with shock peened HSS tool exhibits higher tool life of up to 255 and 85% than the conventional and the hybrid textured (HT) tools respectively. The results shown that surface texturing followed by shock peening is an innovative method to improve the sustainability in machining process than only surface texturing method. Moreover, analysis of chip is studied by finite element analysis.</p>","PeriodicalId":642,"journal":{"name":"Journal of Machinery Manufacture and Reliability","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141170672","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-27DOI: 10.1134/s1052618824700067
A. M. Popov
Abstract
During engineering blasting operations, various man-made elements (particles) can be formed from the structure due to the impact of an explosion, which, as experimental data show, can have a completely arbitrary shape and a fairly large mass and speed. This article is devoted to consideration of the ballistics of elongated elements and the derivation of the calculated dependencies that allow one to estimate the trajectory of their movement.
{"title":"Ballistics of Elongated Man-Made Elements","authors":"A. M. Popov","doi":"10.1134/s1052618824700067","DOIUrl":"https://doi.org/10.1134/s1052618824700067","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>During engineering blasting operations, various man-made elements (particles) can be formed from the structure due to the impact of an explosion, which, as experimental data show, can have a completely arbitrary shape and a fairly large mass and speed. This article is devoted to consideration of the ballistics of elongated elements and the derivation of the calculated dependencies that allow one to estimate the trajectory of their movement.</p>","PeriodicalId":642,"journal":{"name":"Journal of Machinery Manufacture and Reliability","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141170113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-27DOI: 10.1134/s1052618824700110
A. A. Guliev, N. A. Gasanova, T. U. Khankishieva
Abstract
Combined screw joints used in mechanical engineering and oilfield volumetric hydraulic drive devices and other areas are discussed. The possibility of creating combined valves by pressing and casting a part from plastic onto metal reinforcement has been considered. It has been established that the profile and screw pitch should be selected from the same calculation of the strength of the screw from metal and thermoplastic. It has been established that the determining role in the calculation is played by the length of the screw, and the minimum wall thickness is selected using screw profiles. It has been established that the shear strength of thermoplastic materials differs significantly from the shear strength of metallic materials.
{"title":"Research of Strength under Conditions of Uniform Loading of Combined Screw Joints in the Structures of Thermoplast Parts with Metal Fittings","authors":"A. A. Guliev, N. A. Gasanova, T. U. Khankishieva","doi":"10.1134/s1052618824700110","DOIUrl":"https://doi.org/10.1134/s1052618824700110","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Combined screw joints used in mechanical engineering and oilfield volumetric hydraulic drive devices and other areas are discussed. The possibility of creating combined valves by pressing and casting a part from plastic onto metal reinforcement has been considered. It has been established that the profile and screw pitch should be selected from the same calculation of the strength of the screw from metal and thermoplastic. It has been established that the determining role in the calculation is played by the length of the screw, and the minimum wall thickness is selected using screw profiles. It has been established that the shear strength of thermoplastic materials differs significantly from the shear strength of metallic materials.</p>","PeriodicalId":642,"journal":{"name":"Journal of Machinery Manufacture and Reliability","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141170373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-27DOI: 10.1134/s1052618824700080
V. V. Stolyarov
Abstract
Based on literary and experimental data, the effects accompanying the passage of pulsed current and associated structural changes in metals and alloys have been considered briefly. The special role of the type and modes of current, as well as the nature of the material, has been shown. The results of studies of the interaction of electric current and plastic deformation by quasi-static tension in pure metals, titanium alloys with martensitic transformation, and steels have been presented. It is assumed that the causes of the detected deformation effects are the ratio of the period and duration of the pulse, cycling of stress and temperature, changes in the deformation mechanism, reversible transformations, changes in grain size, and the appearance of particles of second phases. Variation of the duty cycle makes it possible to regulate the ratio of thermal and electroplastic effects and thereby influence the mechanisms of hardening/softening.
{"title":"Atypical Hardening Caused by Current and Plastic Deformation","authors":"V. V. Stolyarov","doi":"10.1134/s1052618824700080","DOIUrl":"https://doi.org/10.1134/s1052618824700080","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Based on literary and experimental data, the effects accompanying the passage of pulsed current and associated structural changes in metals and alloys have been considered briefly. The special role of the type and modes of current, as well as the nature of the material, has been shown. The results of studies of the interaction of electric current and plastic deformation by quasi-static tension in pure metals, titanium alloys with martensitic transformation, and steels have been presented. It is assumed that the causes of the detected deformation effects are the ratio of the period and duration of the pulse, cycling of stress and temperature, changes in the deformation mechanism, reversible transformations, changes in grain size, and the appearance of particles of second phases. Variation of the duty cycle makes it possible to regulate the ratio of thermal and electroplastic effects and thereby influence the mechanisms of hardening/softening.</p>","PeriodicalId":642,"journal":{"name":"Journal of Machinery Manufacture and Reliability","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141170142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-27DOI: 10.1134/s1052618824700055
A. M. Keropyan, A. Yu. Albagachiev
Abstract
As a result of theoretical studies, it was established that the coefficient of friction of the interacting surfaces of rail vehicles is significantly influenced by the roughness of the contacting surfaces, the actual contact area, the temperature in the contact zone of the wheel-rail system, and the speed of mutual sliding (slip) of the contacting surfaces. It has been established that, in order to ensure the strength criterion and reduce wear, it is necessary to limit the temperature in the contact zone of the wheel–rail system within 300°С by controlling the sliding speed of the wheel relative to the rail. It has been revealed that the effective functioning of the wheel–rail system can be realized through the interaction of the machined working surfaces of the wheel and rail with roughness Rz 20–40 µm. Implementation of the proposed technical solutions using tribological research methods will allow for the possibility of increasing the friction coefficient of wheel–rail systems by up to 27%.
{"title":"Study of the Main Factors Affecting the Increase in the Friction Coefficient of Interacting Surfaces of Rail Vehicles","authors":"A. M. Keropyan, A. Yu. Albagachiev","doi":"10.1134/s1052618824700055","DOIUrl":"https://doi.org/10.1134/s1052618824700055","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>As a result of theoretical studies, it was established that the coefficient of friction of the interacting surfaces of rail vehicles is significantly influenced by the roughness of the contacting surfaces, the actual contact area, the temperature in the contact zone of the wheel-rail system, and the speed of mutual sliding (slip) of the contacting surfaces. It has been established that, in order to ensure the strength criterion and reduce wear, it is necessary to limit the temperature in the contact zone of the wheel–rail system within 300°С by controlling the sliding speed of the wheel relative to the rail. It has been revealed that the effective functioning of the wheel–rail system can be realized through the interaction of the machined working surfaces of the wheel and rail with roughness <i>Rz</i> 20–40 µm. Implementation of the proposed technical solutions using tribological research methods will allow for the possibility of increasing the friction coefficient of wheel–rail systems by up to 27%.</p>","PeriodicalId":642,"journal":{"name":"Journal of Machinery Manufacture and Reliability","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141170374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号